1. (Field of the Invention)
The present invention relates to an outline forming method for a resin-sealed type semiconductor device using a film carrier and relates also to a semiconductor manufacturing device used in this method.
2. (Description of the Related Art)
Using a tapelike film carrier formed from an organic film is known as one of manufacturing methods for a semiconductor device. A relational manufacturing method for a resin-sealed type semiconductor device using such a film carrier will now be described with reference to FIGS. 9A to 12. The manufacturing method shown is of a BGA (Ball Grid Array) type. FIGS. 9A and 9B are a plan view and a sectional view, respectively, of a film carrier in the related art; FIG. 10 is a sectional view of a molding die in the related art; FIG. 11 is a sectional view of an outline forming die in the related art; and FIG. 12 is a side view showing the shape of a molded package of a semiconductor device manufactured by the related art method.
Referring to FIGS. 9A and 9B, reference numeral 1 generally denotes a film carrier including a tapelike film 2 formed from a polyimide film or a polyester film, a plurality of circuit patterns 3 formed from a copper foil, and an insulating film 5 for insulating a semiconductor chip mounting portion. The circuit patterns 3 are formed on the film 2, and the insulating film 5 is formed on the film 2 so as to cover the circuit patterns 3. The film 2 is formed with a plurality of through holes 7 arranged regularly and exposed to the lower surface of the film 2, so as to take the circuit patterns 3 formed on the upper surface of the film 2 from the lower surface of the film 2 as electrodes.
As shown in FIG. 10, a semiconductor chip 9 is bonded to the semiconductor chip mounting portion of the film carrier 1 by means of a die bonding material (not shown). A plurality of electrode pads formed on the upper surface of the semiconductor chip 9 and a plurality of bonding portions on the circuit patterns 3 are connected through gold wires 11 on a hot heat column (not shown).
In a resin molding step, the film carrier 1 on which the semiconductor chip 9 is mounted is set in a molding die 13 as shown in FIG. 10, and a melted resin 15 to be molded is injected from a gate of the molding die 13 to seal the semiconductor chip 9, the gold wires 11, and the circuit patterns 3 with the resin 15.
The molding die 13 is composed of an upper die 13a and a lower die 13b. The upper die 13a is recessed by electrical discharge machining of a steel material in general to form a cavity 17. A pressure rib (clamp) 19 is formed around the cavity 17 by grinding, so as to prevent leakage of the melted resin 15 from the cavity 17 in injecting the resin 15 into the cavity 17 with the film carrier 1 sandwiched between the upper and lower dies 13a and 13b. To this end, when the film carrier 1 is sandwiched between the upper and lower dies 13a and 13b, the lower end surface of the clamp 19 is set lower in level than the upper surface of the film carrier 1 around the clamp 19 by several micrometers. That is, the film carrier 1 is depressed to be slightly recessed by the clamp 19, thereby preventing leakage of the melted resin 15 from the cavity 17.
After sealing the semiconductor chip 9, the gold wires 11, and the circuit patterns 3 with the resin 15, a plurality of solder ball electrodes 21 are formed at external electrode portions on the back surface of the film carrier 1. Thereafter, the molded package with the film carrier 1 is set in a dedicated outline forming die 23 as shown in FIG. 11 to carry out an outline forming step. The outline forming die 23 is composed of a stripper 25, a die 27, and a cutting punch 29. The film carrier 1 is held by the stripper 25 and the die 27, and a peripheral portion of the film carrier 1 projecting from the outer circumference of the molded package is cut off at a given position by the cutting punch 29, thereby forming the outline of a resin-sealed semiconductor device 31.
In the relational manufacturing method mentioned above, however, it is necessary to ensure a margin for absorbing a dimensional error of the molded part or variations in setting position or ensure a film pressure area 33 (see FIG. 11) in the outline forming step. As a result, the size of the film carrier 1 after cut becomes larger than the size of the molded package by about 0.3 to 0.5 mm as shown in FIG. 12. Thus, the film carrier 1 after cut projects from the outer circumference of the molded package.
Accordingly, when a force F is applied to a projected portion la of the film carrier 1 in a measurement or inspection step or during transportation, the film carrier 1 may be separated from the molded package to cause a deterioration in air tightness (especially, moisture resistance) of the package.
Further, in the case that the package is deformed by the application of the force F to the projected portion 1a, the size and shape of the package are changed to cause a difficulty of recognition of the outline of the package at a mounting machine.